As shown in FIG. 1, to make hacking harder, one hardware encryption key 114 can be used for most significant bits 118 of a data word and another 116 for least significant bits 120 (HW KEY 1, HW KEY 2). Likewise, software control can be implemented, so messages received from or delivered to one communication channel, application program, etc., can be encrypted/decrypted by one hardware key; while those from or to another communication channel, application program, etc., are encrypted/decrypted by another hardware key.